This invention relates to recycling and, more particularly, to recycling glycol that is mixed with various other types of substances.
Glycol is well known and used in a variety of different applications. For example, glycol has a relatively low freezing point (˜65° C.), which makes it attractive for use as an anti-freezing fluid in vehicles and other systems. One particular use of anti-freezing fluids occurs at airports for de-icing aircrafts before take-off. Typically, an aircraft is sprayed with a de-icing fluid that contains glycol to eliminate ice accumulation and prevent freezing of water on the aircraft. Spent glycol is then either released into the environment or collected within a collection system. Due to environmental concerns, the glycol is preferably collected rather than released.
Typically, the spent glycol is polluted with water, fumes from the aircraft, solid debris in the collection system such as leaves, grass, etc., and other substances. The spent glycol is not reused in this polluted state. Typically, the airport pays a fee to dispose of it. However, some airports employ a system to recover a portion of the glycol. For example, the spent glycol is collected in a reservoir wherein the undesired substances, which are generally lighter than the glycol, float on top of the glycol. The top is then ignited to burn off the undesired substances (often referred to as “flashing”) to produce purer glycol. One drawback to flashing is that it is difficult to obtain highly pure glycol. Other recovery systems include aerobic digesters and distillation columns, however, these systems are prone to leaking, employ relatively expensive equipment, and can be relatively expensive to operate. Additionally, even if the glycol is recovered using any of the above systems, no use is made of the substances that are mixed with the glycol.
Accordingly, there is a need for a recycle system for recovering a spent substance such as glycol and also recovering or using the other substances mixed with the spent substance. This invention addresses those needs while avoiding the shortcomings and drawbacks of the prior art.